Why does my Advance Multiplier keep dropping?

[jeebus]

I think I seem to have found the pattern. Around 3400RPM @ .9 engine load during cruise conditions (driving up a hill in this case). I'll dial back timing a tad and see how it goes.

[jflogerzi]

so any drop in the IAM below 1 is a sign of knock and the engine will pull timing to compensate?

[SirBrass]

Originally Posted by jflogerzi

so any drop in the IAM below 1 is a sign of knock and the engine will pull timing to compensate?

Yes. Any multiplier (DAM) below 1 reduces the timing.

[garfull]

still trying to understand what the KC learned value is and what it should be.

KC = knock correction?

[steve99]

Originally Posted by garfull

still trying to understand what the KC learned value is and what it should be.

KC = knock correction?

Jamesm explained it to me

You need to look at the Engine RPM Vs Load table in tunepro/romraider ect and look at the value in the table for the given RPM vs Load. If that value is say 6 and your KC Learned is say 2 then it means its pulled 4 degrees of timing at that RPM/load point.

If the value in the RPM vs Load table equals the KC Learned then their is no knock retard at that rpm/load.

Hopefully I got it right.

[PMok]

so I did another run today on a full tank of 91, with similar results.

http://www.datazap.me/u/pmok/stage-1...og=0&data=1-12

Adv. Multiplier was around 0.52 when I started the car. As you can see it went back up a little during the run, but still nowhere near 1.00 at all. Thoughts/recommendations? Assume that I have no tuning skills at all and very little inclination to get too involved into it. Should I be worried enough to switch back to stock tune, or find a way to get higher octane gas?

[garfull]

Try recording some runs on the stock tune to see if u still have similar results.

Originally Posted by PMok

so I did another run today on a full tank of 91, with similar results.

http://www.datazap.me/u/pmok/stage-1...og=0&data=1-12

Adv. Multiplier was around 0.52 when I started the car. As you can see it went back up a little during the run, but still nowhere near 1.00 at all. Thoughts/recommendations? Assume that I have no tuning skills at all and very little inclination to get too involved into it. Should I be worried enough to switch back to stock tune, or find a way to get higher octane gas?

[connorlug]

Originally Posted by jeebus

I had the best luck with 76 in my modded Forester XT...so it doesn't sound odd at all. However, I had the best luck quieting the crickets with Chevron which is why I stuck with it. That, and every convenient stop on my commute is Chevron....however, I'll give 76 a whirl if I don't just run e85 all the time.

Sorry to randomly chime in, but I also used to have a modded forester xt... were you on the sf.org forums?

[steve99]

Originally Posted by garfull

Try recording some runs on the stock tune to see if u still have similar results.

+1

Be interesting to see if it was happening on standard tune

Pmok are you at significant altitude above sea level ?


PMok you could

Source some higher octane fuel
add octane booster to current fuel
Pull some timing in the problem area's (although you stated you don't want to get involved in doing that)
Run E85 and E85 tune

[PMok]

Originally Posted by steve99

+1

Be interesting to see if it was happening on standard tune

Pmok are you at significant altitude above sea level ?


PMok you could

Source some higher octane fuel
add octane booster to current fuel
Pull some timing in the problem area's (although you stated you don't want to get involved in doing that)
Run E85 and E85 tune

Yeah I will try logging at stock tune and see if I get similar results. Was wondering if anyone would say to let it keep learning a little more or what. I live in the hills about 1200ft above sea level but the logging and most driving is done pretty close to sea level.
Thanks guys!


Sent from my iPad using Tapatalk

[jeebus]

Originally Posted by connorlug

Sorry to randomly chime in, but I also used to have a modded forester xt... were you on the sf.org forums?

yeah, long time ago. same username.

[jamesm]

i've fought tip-in knock with this thing since i started tuning it. I've tried all sorts of stuff, from the regular timing adjustments to throttle mapping and cam timing. Nothing so far has worked. Not even E85 lol. You can make it happen less often, and you can make it less severe (where you may see up to -2.1's you can get it to only ever pull -1), but I haven't found a way to eliminate it entirely. I've got it down to one or two instances in a 20-30 minute log at best.

My next plan is a custom map that'll pull timing based on throttle delta. If that doesn't work, i'll try the same thing with MAP delta.

The hack around the IAM dropping is just to make sure the value in the advance map where it happens is less than 3.9 (while keeping the same total timing).

[atledreier]

Bob at Circuit Motorsport fixed my tip-in knock. No idea what he did, though.

[Kodename47]

Originally Posted by PMok

so I did another run today on a full tank of 91, with similar results.

http://www.datazap.me/u/pmok/stage-1...og=0&data=1-12

Adv. Multiplier was around 0.52 when I started the car. As you can see it went back up a little during the run, but still nowhere near 1.00 at all. Thoughts/recommendations? Assume that I have no tuning skills at all and very little inclination to get too involved into it. Should I be worried enough to switch back to stock tune, or find a way to get higher octane gas?

The IAM will not start to increase until the engine is satisfying certain RPM and load parameters. IAM will not try and increase during low load (normal low RPM) driving.

Basically, most of the 2nd half of that log the ECU isn't even trying to increase timing, that may not be due to it seeing knock etc. Its not ideal that its starting at 0.52. Its hard to tell if its pulling timing during the WOT pulls as you've not repeated them so there's nothing to compare.